A familiar example is seen in the moose, which permits various birds to run over it, in all probability in search of insects. The hunter stealing upon the animal may find it asleep in some out-of-the-way nook; but the watchful jay is on guard, and, uttering its note of alarm, the moose springs to its feet and rushes away. That this animal submits to the attention of the jay is well known, the bird having been observed running over its body with the greatest freedom.
In Central America, especially in Nicaragua, a singular bird, called quiscalus, is very assiduous in its attentions to wild cattle, taking its place on their backs and elevating and depressing its long neck and tail in a remarkable manner. But does an enemy approach, the black, grotesque creature immediately utters discordant shrieks which have an immediate effect upon the cattle, who toss up their heads and rush into the bush.
In Africa this guardianship between birds and oxen is so well established that certain birds are universally known as oxbiters. One of the best known of these feathered guardians is the red-beaked oxbiter, a little bird not larger than a robin, with a deep red beak and eyes that sparkle with a golden gleam. Wherever wild cattle, large antelopes, the camel, rhinoceros, or elephant are found there will the guardians be seen, perching on their backs or running over them with an audacity that is amazing. On the camel the oxbiter will run up the woolly neck like a woodpecker, perch upon the ear of the patient animal and examine it intently, while others cling to various parts of the creature, which is perhaps half asleep.
So watchful are these sharp-eyed birds that at the first suggestion of an enemy's approach the birds rise from the backs of the herd, uttering loud and discordant cries, which are interpreted at once. At the first warning note the huge animals rush blindly into the bush, leaving the sportsman mortified at his seeming lack of skill in stalking big game.
Rhinoceros Birds.
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One species is called the rhinoceros bird on account of its partiality to the rhinoceros, numbers being seen clinging to the hide of the big animal or perching upon its ears and horns.
Drummond, the well-known naturalist, found it extremely difficult to deceive these watchful guardians. On one occasion he had stalked a Cape buffalo and a water antelope for hours, never exposing himself, knowing that the birds were on guard. Finally he reached a situation favorable to a shot, when an eagle-eyed bird uttered a sound like "tcha-tcha," and the entire flock rose into the air with loud cries, at which the ox and antelope dashed into cover.
That these feathered guardians are attached to the animals is suggested by the pertinacity with which they cling to them. A hunter had succeeded in approaching a rhinoceros, when the birds gave the alarm and away dashed the big creature. Some of the birds hovered over the flying animal, but several clung to its hide, often brushed off in the flight through the brush, but renewing their position despite the wild race.
When the rhinoceros was finally killed the birds clustered in the neighboring trees. The following day, when the sportsman returned to skin the animal, the little guardians were found sitting on it, and when the native gun-bearers appeared they uttered their alarm cry and even brushed their wings in the face of the dead rhinoceros in their efforts to arouse it.
The sluggish hippopotamus and the elephant serve as a perch for a small white heron which is extremely watchful, rising at the slightest alarm, the flapping of its wings being the signal at which the animal steals quietly away, to be rejoined, in all probability, by the white sentinel.
This singular guardianship is not confined to quadrupeds exclusively; certain birds are known to extend a limited protection to other birds, an interesting example being found in northern Africa, where a copper-colored flycatcher has been observed standing guard upon storks. The latter were walking along sedately, feeding upon the myriads of locusts which covered the ground, and upon the back of nearly every one was a flycatcher. The observer, who was a naturalist, watched the birds for some time until one of them espied him, when the entire flock rose, uttering loud cries, which so alarmed the storks that they too took flight. The wattled starling stands guard on various birds, and has seriously interfered with the plans of many sportsmen.
In various countries this singular instinct or guardianship of certain birds is taken advantage of. Thus the wing-spurred chauna, of South America, is sometimes found in the dooryards of well-to-do natives acting the part of a guard to its owner's property. The bird is remarkable for its pugnacity; and its cry, a harsh, penetrating scream, is sufficient to demoralize a much larger foe. These birds are placed in the farmyard when young, and are considered a safeguard against hawks and various predatory animals. Shepherds employ them to guard their flocks, and more than once the wing-spurred bird has stood between the lambs and the puma, proving itself one of the most effective of the feathered guards.
PRISONERS FOR LIFE.
A CAPTAIN of a vessel once brought from the Philippine Islands an object which he claimed was the skeleton of an animal that had been taken from the deep sea of these islands. It was tubular in shape, about two inches across and eight inches high, and made up seemingly of white, silvery spun glass, worked and woven as if by fairy hands, so that it presented a reticulated surface and a general structure so marvelous that not a few persons who saw it believed it to be some cunning work of the Chinese or Japanese, whose strange productions are so fanciful in their design, and were then just becoming known. Scientific men, however, pronounced the rich vase the framework of a silicious sponge, and named it the Euplectella. It is commonly called "Venus's flower basket."
Venus's Flower Basket.
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If we examine one we shall find that the little square portholes or reticulations are a prominent feature in its formation, the little windows being just large enough for a very small animal to creep or crawl through. One day while examining the structure of one of these vases, I noticed two little claws of a crab reaching out toward me, each one being extended through a porthole, if so we may term the little orifices. By cutting away a portion of the vase a good view of this inhabitant of the sponge was obtained, and a melancholy spectacle it was, for here was a crab that through mere curiosity in its youth had strayed into the sponge, and, like the prisoners of old, had been literally walled in. It had grown so large that escape was impossible; and finally, when the sponge died, it was found with its claws extending through the bars of the prison as though imploring aid.
The crab had entered the sponge when it was a minute creature known as a zoea. It soon grew too large to escape, and had lived upon the sponge, or the food wafted in, and was found only when the beautiful sponge died and was deprived of its rough and unsightly exterior. Among the crabs we find many prisoners; thus the little forms that live in oysters are prisoners in the shell; resting among the soft folds of the oyster they pass their time, rarely, if ever, venturing forth, and feeding upon the various objects that are wafted into the mollusk by its cilia.
The old naturalists, as Pliny, were familiar with many prisoner crabs, as there are several bivalves that possess them, and believed that between the ill-sorted pair there was a partnership to the effect that the shell should provide the crab with protection, and that the latter should keep a "weather eye out" in the interest of its host, a sly pinch from one of the biting claws being the signal for the valves to close. Undoubtedly the oyster received many signals, but I am afraid they were all in the interest of the crab, and were attempts to dine upon its host.
The barnacles, cousins of the crabs, might be termed prisoners, as they are unable to move from where they take their original stand, though many fasten themselves to moving objects, and so lead a compulsory roving life. One is found growing upon the feathers of the penguins in the South Pacific, and I have taken a goose barnacle from the mouth of a sunfish—a curious prison indeed, where the stalk was just long enough to prevent its being crushed by the curious teeth of the huge mola.
One of the strangest prisoners to be found anywhere is the little eel or lancelike fish fierasfer. Nearly all the members of the family appear to lead a life of singular retirement. I found my first specimen in wading over the Florida reef, about sixty miles beyond Key West. I had lifted a long sea cucumber or holothurian from its bed on the soft sand of the atoll, and was about to place it in a glass, when, from the creature, appeared the head of the fish. I placed it in the glass tank, and it soon came out, the veriest ghost of a fish, so silvery white that I could almost have read print through it. It swam about for a while, then dropped to the bottom and died at the very moment of its seeming release.
On the reef we often found these curious prisoners, but never without their living prison, and I was forced to believe then that they never, at least at this place, came out. Recent investigations at the Naples aquarium have shown that they do venture into the outer world, and perhaps the most astonishing feature of the entire performance is the return to prison, for the fierasfer is a ticket of leave fish, and reports at headquarters with great regularity.
The curator of the aquarium above mentioned, while watching them, observed one of the fishes approach its living prison, and insert not its head but its tail into the door, and gradually begin to disappear as if some mysterious power were drawing it in, until it had completely disappeared. This curious performance of backing in is conducted by the holothurian itself, which in inhaling water draws the fish in with the current, leaving it finally with its head pointed outward all ready for another journey into the outside world. The fierasfers of some localities live in star fishes, and many, as I have said, have this curious habit assumed after many years. At first it was possibly an accident, but it has grown to be a fixed feature in the life of these fishes.
If we leave the world of the ocean, we shall find many curious prisoners on land. The female hornbill is entombed by her mate in a hollow tree, the latter patiently feeding her through a small window until the egg or eggs are hatched.
Some ants make prisoners not only of their allies, but of beetles and other insects, keeping them in the care of aphides for their so-called milk, and again for the perfume or odor some beetles emit, while many are kept merely as prisoners to act as slaves, and to perform the hard work of the community. In all life we find these strange features, so similar to many of our own, pointing to the assumption that the same general laws and impulses govern all living creatures.